1. Field of the Invention
The present invention relates to a blade structure and, more particularly, to a blade structure used in a blower.
2. Description of the Related Art
Conventional blowers can be categorized into a single side entry blower and a double side entry blower. As for the single side entry blower, the blade structure used in the blower is a blade structure having equally spaced vanes on a single side. That is, as shown in FIGS. 1A and 1B, all blades 11 of the blade structure are provided on one side of a supporting plate 12. A motor drives the supporting plate to rotate the blade structure. However, such kind of blade structure has the following drawbacks. First, if trying to improve the characteristic of wind pressure, it is necessary to increase the number of the blades of the blade structure so as to increase the wind pressure. However, since the space and size of the blades are limited, the increased number of the blades is inevitably limited. Therefore, it is impossible to make any breakthrough regarding the characteristic of the wind pressure. Second, when the blade structure is rotating, the air stream passes through both the air inlet and the smallest clearance between the vanes and the outer casing 13. Since the air passage is reduced drastically from a large size to a small size, the turbulence and noise may be generated easily.
In addition, referring to FIGS. 2A and 2B, the blade structure of another conventional blower includes a plurality of blades 21. The blades 21 are formed at two sides of a supporting annular plate 22 in an opposite manner to reduce the noise. The number of the blades can be doubled with respect to the above-mentioned blade structure so as to improve the wind pressure characteristic without changing the size of the blower. However, since the added annular plate may decrease the working area and block the passage of the air stream, a predetermined wind pressure and gas quantity may be lost.
In view of the above-mentioned drawbacks in the prior art, the present invention provides an improved blower and the blade structure thereof.